P0773 shift solenoid E

[bmw635]

Trying to trouble shoot this P0773 issue in my 80 since rebuit my engine couple yrs ago. Replaced solenoid #3 (#35250-50030) and confirmed that it's dead.

Pull battery to clear everything , no code in ODBII. Go for a drive until trans is hot, ODBII read P0773 but no CEL. Some time CEL pop up, some time no CEL at all. Could a bad ECM/TCM cause this?

Since this code pop up right after my engine rebuild, could a missing ground strap cause this?

Any other ideas? TIA.

 

[bmw635]

Anybody? bump from 2nd page.

 

[Malleus]

 

[Malleus]

Yes, to answer your first question, it could be that simple, but I'd bet it's either a connector related problem (if you've replaced the malfunctioning solenoid with a good one) or a harness problem, and not a ground per se.

You really need a Factory Service Manual to do this properly, there's a lot going on here. From the DTC chart, this is a one time failure, either open or short, so you have to check for both (see above).

There is an extensive troubleshooting section in the Automatic Transmission manual (RM479U). If you don't have one, you can download the entire vehicle manual for $15 here:
https://techinfo.toyota.com/techInfoPortal/appmanager/t3/ti?_nfpb=true&_pageLabel=ti_home_page&contextType=external&username=string&password=sercure_string&challenge_url=https://techinfo.toyota.com/techInfoPortal/login/techinfo&request_id=-1834742629047839760&authn_try_count=0&locale=en_US&resource_url=https%3A%2F%2Ftechinfo.toyota.com%2Ft3Portal%2Fappmanager%2Ft3%2Fti%3F_nfpb%3Dtrue%26_pageLabel%3Dlib_repair_sum
Even if you prefer paper manuals, there's a lot to be said for the PDF version. Try it, you may like it.

 

[bmw635]

Thanks for details. Looks like I gotta go deep.

Found 2 local ECU to swap and code still persist but no CEL. I think if engine is cold, no code or CEL.

I checked the 2 pins (forgot wire color) from trans connector from ECU to plug on rear driver of trans (solonoid) , and wires are not broken.

New Toyota solonoid checked and installed, wires not broken, ECU(3) is ok so could speed sensor (no code) or missing ground strap from body to trans cause this code?

Looking at my old post, this started after engine rebuild so may be the missing ground strap? I am trying to find the diagram showing all ground strap to verify nothing is missing.

Will go through the details you provided later on. Thanks.

 

[bmw635]

Found the problem. Corroded Red/Blue stripe wire for solonoid #3 (torque converter lockup.

I have a spare 2 pin connector from the knock sensor. Removed 1 of the pin by prying open the white housing from the black housing in the connector then push the plastic tab away from the pin then use 2nd pick pushing the pin out.

Do the same on the connector on the trans bell housing. Solder new pin into wire and reinstall. Don't forget the silicone seal on top of the pin before soldering. Reassemble the connector and plug back in.

 

[FredZ]

Found the problem. Corroded Red/Blue stripe wire for solonoid #3 (torque converter lockup.

I have a spare 2 pin connector from the knock sensor. Removed 1 of the pin by prying open the white housing from the black housing in the connector then push the plastic tab away from the pin then use 2nd pick pushing the pin out.

Do the same on the connector on the trans bell housing. Solder new pin into wire and reinstall. Don't forget the silicone seal on top of the pin before soldering. Reassemble the connector and plug back in.

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BMW635,
My 97 TLC showing code P0773 & experiencing intermittent Transmission shifting issues. I wonder if you could tell me where is the location of Shift Solenoid #3 so I can check those wires for corrosion. Any picture or detailed info are welcomed.

Thanks,
Fred